Otter welfare is closely tied to river food availability and territory quality. Understanding their ecological needs reveals the welfare implications of river management decisions.
Otter welfare mirrors river ecosystem health. An otter in a high-quality river with abundant fish, clean water, and undisturbed holts has an excellent welfare quality of life - as demonstrated by their playful behaviour and successful breeding in restored river systems. Welfare deteriorates when prey is scarce (through overfishing, pollution, or habitat degradation), holts are disturbed, or territorial defence requires constant energy expenditure. The collapse of European eel populations has removed a key historical prey species from otter diets - a welfare change that forces dietary adaptation to smaller, less energetically profitable prey. Supporting eel recovery alongside broader river restoration is an otter welfare priority.